As any good Republican, one of my favourite passe-temps is hating on new things, particularly technology.i
But every heuristic has its limits, statistics not applying to individuals and all that, so go figure that I’d find myself being frustrated to all hell with Jay on a very prototypical day in the Great White North, one where it snowed from sunrise to sunset and the thermometre never ticked above -15C, persistently annoyed with his inability to get off the frozen line without spinning his big fat rears, only to have his black ass save my bacon and that of l’enfant in one fell swoop.
Almost as if it was listening to me in-channel,ii I was driving home from the office via the daycare at the club, gingerly nursing the big nig from street to avenue between 40 and 50kph, well below the posted limit of 60kph but in-line with traffic and very much commensurate with the weather, when, about 2/3 of the way home and not 500m from where I grew up, a Buick crossover decided to turn left in front of me. No problem, even in those conditions, as I’d been giving it some 15 car lengths of liebensraum. Needing to wait for oncoming traffic to clear, the Buick rolled to a complete stop at the intersection. Thankfully, it was a two-land road that was empty to my right so I easily changed lanes to get around the guy, thus avoiding having to come to a complete stop and opening myself up to the non-trivial risk of being rear-ended by some dork sexting his boyfriend while driving his half-ton without proper winter tires.iii So then I was in the right lane and about to pass the now-parked Buick and continue cruising home on my merry way home. NBD, right ?
If only. As I approached the intersection where the Buick is turning left, now not 40 feet away, some confused-as-fuck Mexican in a Hyundai Tuscon decided that he was going to leave his safe little perch perpendicular to my line of travel and turn left across the Buick, myself, and into the oncoming traffic that the Buick is waiting for. Chico had nowhere to go, obviously, and yet he saw fit to select that particular moment in his short, short lifeiv to thrust the nose of his Hyundai fully 10 feet ahead of where it was safely stopped and leave it fully halfway into the intersection that I was about to steam through. With nary a moment’s warning and traveling at easily 40kph, it was all a fast-reacting, well-trained,v and son-transporting driver could do to avoid the Tuscon, the Buick, the curb, the traffic pole, and oncoming traffic, all while navigating dark roads covered in black ice in a two-tonne RWD luxury sedan.
I can tell you right now that had I been driving Saddam as I’d threatened to, I would’ve barrelled straight into ese. I can guarantee you that. No amount of locking diff in the world could’ve saved me in that situation. Under braking, all that matters is surface area, surface area, surface area. And when it comes to surface area, Jay has top trumps on Saddam. By a huge margin.vi
Without that card to play, I can promise you that I would’ve plowed straight into holmes instead of being able to calmly find my braking point, find the maximum purchase from the tires, swerve left to avoid the Mexican, swerve right to avoid oncoming traffic (basically executing an intentional four-wheeled tank slapper), and not spin out into either. Thanks to Jay, bless his dark soul, instead of being in an full-on collision with my sleeping toddler in tow, I was able to remain in complete control of the vehicle, leaving only my emotions to bubble over, and even then only once I’d executed the maneuver and was through to the other side of the test.
So thanks progress, I owe ya one.
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- Really, it’s modernity in general that doesn’t sit so well. Except for when it does, of course. ↩
- To quote from the logs not an hour before the incident to be described herein :
pete_d: Speaking of which, fucking terribad roads today. Made me yearn for G-Wagen. Whoever the fuck thought that an open rear diff could be compensated for by electronic nagging should spend the rest of their lives in Noyabrsk.
ben_vulpes: What nagging pete_d ?
pete_d: Beeping and flashing orange dash light every time Traction Control activates, which in RWD car with 275* rear section tires on freshly snowed roads is… constant.
ben_vulpes: Aha k. Beeping too?
pete_d: The beeping only comes on when TC is REALLY going hard, but flashing dash light flickers with the mildest invocation.
ben_vulpes: Yeah non-locking rear is an odd duck. “Fuel economy” is the argument, right?
pete_d: It’s goddam inexcusable. I think ‘progress’ is the going claim for open diff v. rear locking diff. ‘Saddam’ my 27yo Merc WITH LOCKING DIFF will be taking over DD** duty, despite having a much shittier heater, until the roads are cleaned up.
**DD = Daily Driver ↩
- Proper winter tires are Michelin X-Ice and Bridgestone Blizzak. Nought else. ↩
- Mexicans aren’t exactly known for their prodigious heights. ↩
- That Mercedes-Benz Winter Driving Academy from a few years ago continues to pay dividends. ↩
- Let’s do the quick math. Both vehicles weigh about 4`200 lbs unladen by occupants so it comes down to wheels and brakes for the difference makers :
Lexus LS460L – 245/45R19 vs. Mercedes 560SEL – 215/65R15
Assuming that the contact patch between each tire and the ground is 15% of the circumference, the Lexus has ((19*25.4)+(2*0.45*245))*π*0.15*245*4 = 3247cm² of total contact area with the ground vs. ((15*25.4)+(2*0.65*215))*π*0.15*215*4 = 2677cm² for the Mercedes. A difference of 21%.
Lexus LS460L – Front : Four-piston calipers, 380.2mm discs. Rear : Two-piston calipers, 315.0mm discs.
Mercedes 560SEL – Front : Single-piston calipers, 300.2mm discs. Rear : Single-piston calipers, 279.0mm discs.
Assuming that the pistons are all roughly the same size and that we’re using 140mm x 60mm brake pads on the Lexus and 50mm x 60mm pads on the Mercedes, the former has 140*60*6 = 504cm² vs. 50*60*4 = 120cm² for the latter. A difference of 320%.
Add in that the Mercedes has Bosch-developed ABS that cuts in far too readily, which only leads to longer stopping distances, and that the Lexus is able to electronically catch and correct a drift midway through by selectively braking wheels, and the differences in emergency maneuvering are night and day.
Scholarly, slippery addendum :
While it’s indeed the case that a larger wheel-ground contact patch increases friction and grip thereby decreasing stopping distances, on icy roads, wider wheels are your enemy when getting off the line. Why ? It all comes down to pressure, which is the quotient of force divided by area. To say nothing of the locking rear differential on the Mercedes that sends power to the more slowly spinning wheel when the rates of rotation differ beyond a certain threshold compared to the open differential and electronic supports on the Lexus that send unlimited power to whichever wheel and then use the brakes to slow the rotation of the overburdened wheel, the difference in pressure is significant. Given similar enough masses and virtually identical 54/46 front-to-rear weight distributions, the Lexus applies 0.46*1900*981/3247 = 246N/cm2 over the two rear tires vs. 0.46*1900*981/2677 = 320N/cm2 over the two rear tires in the Merc. A difference of 30%. ↩